Steam heating system



Feb, 23, 1943- J. T. READER 2,312,191 I 'STEAM HEATING SYS':."1'}1\1lFiled OC). 14, 1940 2 SheS-Sheet 1 ATToR f n l V feb 23, 1943' J.TQREADER. 2,312,191

I STEAM HEATING SYSTE.M

Filed .0013. 14, 1940 2 Sheets-Sheet 2 INVENTOR 'ATToR 5.

the delivery' of Steam Patentedv Feb. 23, 1943 orties;

STEAM HEATING SYSTEM Joseph T. Reader, Grosse Pointe,

to synchronised Systems Company, a ship composed of Joseph 'l'. Machrls,Harold E. Rose,

Robert P, Butler Mich., assignorl partnerlteader, Charles E. Albert E.Fisher, and

vApplication october 14, 1940, Senn No. 361,013

12 Claims.

This invention relates to steam heating systems -for buildings andhasfor its principal object the provision of a steam heating system ofimproved characteristics in operation and control and which will eil'ecteconomies in operation.

Objects 'of the invention include the provision of a steam heatingsystem provided with pumping means at the outlet end of the system forpurging the system of non-condensable gases and water of Y condensationtogether with means ,for controlling the flow constructed and arrangedas to tend to reduce vinto the system as each' cycle of voperation ofthe pumping means is initiated; the provision of a Steam heating systemhaving pumping means at the outlet end 'of the system for purging theSame of air, non-condensable gases and water of condensationcyclicallyoperated in accordance of the system, and a pressure reducingvalve for controlling the ilow of higher pressure steam into the inletend of the system, together with control means for'the pressure-reducingvalve so constructed and ,arranged `that at the beginning of each cycleof operation of the pumping means; the pressure reducing valve willte'nd to close and reduce the supply of steam to the system whereby toenable the pumping means to quickly purge the system of the air,non-condensable gases and water of condensation; and the pro vision of asteam scribed in which initial reduction of pressure in the system atthe outlet end thereof upon the initiation ofeach cycle of operation ofthe pumping means is eiiective to 4cause an .initial closing movement ofthe trolling the admission of steam to the'system and until theoperating pressures throughout the system have reached an approximatestate oi equilibri-um.

Other objects .of the invention include the provision of a steam heatingsystem for buildings or the like so constructed the system isautomatically re- .duced as the pressure in the system is reduced; theprovision 'of a steam heating system in which the pressure existing at.the outlet end of the of steam into the System, sov

with the demands heating system of the class depressure diierenceathereby increasing the ef-v fective life of the steam traps.

A' inlet end of the system steam heating system including a. valve forintroducing steam in'to the system. and a vacuum pump at'the discharge'end of the system for maintaining the system under a predetermineddegree of vacuum, sp'onsive to the pressure in the system at thedischarge end and at the inlet end thereof serving to controlv the steamadmittance valve but is so constructed and arranged as to decrease thedifferential of pressureibetween the inlet and outlet sides of thesystem as the degree of vacuum on the outlet end of the system isincreased: and the provision of a steam heating system including controlmeans therefor so constructed and arranged as to relieve steam traps orlthe like employed in the system of excessive Further objects of vtheinvention include the provision of a steam heating system for buildingsor the like in which a|` valve is provided at the for admitting steamfrom a Source of Supply thereto, and a. vacuum pump is .provided at thedischarge end of the system for mamtaining the system under adesireddegree of vacuum, means being PIOvided `for controlling the valvecomprising pressure responsive means including a movable wall connectedto the valve and having one side thereof exposed to the effects o! thepressure at the inlet end of the system and the opposite Side thereofexposed to the effects of the pressure o! the system at the outlet endthereof, whereby it tends to maintain the differential of'pressure inthe system conpressure reducing valve con` h and-arranged thatthe--diiferential of pressure between the inlet and -outlet Sides of stent,together with means for varying the effect of said pressure responsivemeans on said valve comprising an additional pressure responsive elementincluding a movable wall subject to the pressure of the system at the'outlet end thereof on one face thereof and to the atmosphere or othersource of xed pressure on the opposite face thereof and so constructedand connected to the valve as to vary the eilects of the ilrst mentionedmovable wall to decrease the difierential between the inlet and outletends of the system as the degree of vacuum on the outlet end thereof isincreased: and the provision of a construction as above described inwhich the change relative areas of the two pressure responsive ele'-ments may be changed to enable the rate of oi the pressure differentialof the' system between maximum and minimum values to be varied to meetthe requirements of the rnaximum and minimum pressure differentialsrequired inthe system.

together with means :re-l

of the type described in which means are provided for shutting on' thesupply of steam to the system whenever the primary pressure responsiveelement is ruptured to Ysuch an extent as to prevent yits functioning;the provision of a steam heating system of the type described employinga pair of pressure responsive'elements for controlling the pressurereducing valve so constructed and arranged that the introduction ofsteam to the system at excessive pressures will automatically cause thepressure reducing valve to be closed, thereby to shut oi the iiow ofsteam to the system; and the provision of safety means in a structure ofthe type described which will automatically prevent undesirable `highsteam pressures to be built up in the system.

The above being among the objects of the present inventionthe sameconsists in certain novel features of construction and combinations ofparts to be hereinafter described with reference to the accompanyingdrawings, and then claimed, having the 'above and other objects in view.

Fig. 1 is a more or less diagrammatic, frag-4 In the accompanyingdrawings which illustrate A type of steam heating system of the vacuumtype that has recently met with a considerable amount of successincludes a pressure reducing valve at the inlet side of the system tothe stem of which is connected a diaphragm enclosed in a casing forminga chamber at each side of the diaphragm. The chamber on one sideof the-mentary view of a steam heating system constructed in accordance withthe present invention;

Fig. 2 is an enlarged, transverse sectional view taken centrallythrough'the steam control valve mechanism shown in Fig. l;

Fig. 3 is an enlargedvfragmentary, vertical sectional view takencentrally through a modiiled diaphragm construction which may beemployed in place of the diaphragmconstruction shown in Fig. 2, toobtain the same result; and,

Fig. 4 is a view similar to Fig. 2 but illustrating i a modified form ofconstruction. The present invention relates to those types of steamheating systems for buildings or the like in which steam from a suitablescurce of supply is passed through a pressure reducing valve into theheating main at the inlet side of the system, and in which suitablepumping means are provided at theoutlet end of the system for removingthe air and non-condensed vapors,

gases and water of condensation from the system, as well'as to maintainthe outlet side of the system under pressures of suitably low value.

Although it is possible to use the present inven-` tion in connectionwith systems maintained wholly or partly-at or above atmosphericpressures, it will usually be employed in conjunction with so-calledvacuum systems in which the outlet side of the system in particular ismaintained under a partial vacuum or sub-atmospheric pressure, as thesesystems are capable' ofemploying exhaust gases from steam operatedturbines, en-

gines or the like and in any event, regardless of y the source, aregenerally recognized as more ef' ficient and ,economical in operationthan other types of heating systems. Accordingly, while for the purposeof brevity'in description the dis-Y cussion of the' present inventionwill be limited to its application to the vacuum type of systemj' itsapplication to other .t'ypes f systems will bereadily recognized bythose skilled inthe art upon' the disclosure herein without the.necessity of further explanation o1'- vthe present invention thereto. A

diaphragm is connected to the steam main of the system immediatelyadjacent the point at which the reducing valve introduces steamthereinto, suchchamber being the' one in which the presence of a vacuumtherein, if the opposite face of the diaphragm were subjected toatmospheric pressure, would tend to open the valve. The oppositechamber, that is the chamber on the opposite side of the diaphragm isconnected to the discharge side of the system and preferably to thevacuum return line thereof directly connected-to the vacuum or otherpressure reducing pumping means positioned at that point. It will beappreciated that the resuitfof thisconstiuiztion is the provision of anautomatically operated pressure reducing valve controlling theadmittance of steam to the system and serving to maintain a constantdifferential of pressure between the inlet and outlet sides of thesystem regardless of variations of pressure at the outlet side of thesystem. The amount of dierential pressure maintained between the inletand outlet side of the system is controlled by means of springs, weightsor the like `constantly acting 'on the valve, through the diaphragm orotherwise, tending to move the valve either towards closed or openposition and usually towards open position.

The above described heating system was a material improvement in theartfor the reason that the engineer or other operator of the system couldvary the flow oi.' steam through the system to accommodate thevariousheating requirements by simply varying the degree of vacu` 'In otherwords, the engineer could adjust the vaccum pump to produce a lesserdegreeof vacuum and the pressure reducing valve a greater degree ofdiil'erential when the heating requirelments of the system increased,and 'adjust 'the vacuum pump to provide a greater degree of vacuum -andthe pressure reducing valve a lesser degree of differential when theheating requirements of the system decreased. However, when the vacuumpump is operating after starting up automatically, the constantdiiferential reducing pressure valve remains open and admits excesssteam to the inlet side of the system because, `as the vacuum increaseson` the lower side of the diaphragm, whichv is connected to the returnend ofthe system, the vacuum onV the upper side of the diaphragm whichis connected to the inlet side of the system increases correspondinglyand the opening through the valve `tends to remain unchanged. 'I'hesupply pressure to this valve is, of course, not changed '..n anyrespect'because of the operation of the vacuum pump, the pressure at thedown-stream A side of the valve is reduced by operation of the atinglunder this l As readily understood inthe art, the higher -Y pump andconsequently a greater amount of steam flows to the system when the pumpis opermethod of operation.

- the absolute pressurein a heating's'ystem oi the type described thegreateris the pressure diifer- 'loss due to steam -ential of entialrequired between `the inlet and outlet sides of the system to obtain theproper flow of steam through the system to obtain uniform heatingflowing through the system. The greater degree v ythe differential ofpressure vas the absolute -pressure in the systemis lowered has alreadybeen recognized, and one 'result is shown 1n United states LettersPatent of vacuum on the steam .in the system, the less pressuredifferential is required to cause the proper flow thereof throughv thesystem. because the quantity and specific gravity of the steam flowingis less and the drop in pressure required for a proper flow is lessbecause of the smaller frictional losses. Accordingly, with the systemdescribed, conventional practice is to adjust the pressure reducinglvalve, vas lby shifting of theweight orweights thereon, varying thetension -of the spring or springs thereof, or otherwise, so as to obtainthe desired differential of pressure between the inlet and outlet sidesof the system under conditions of-maxlmum heating requirements. If,under such conditions, minimum heating requirements are attained, thesame differential of pressure between the inlet and. outlet sides of thesystem still-remains unless the operator adjusts the pressure reducingvalve itself. as by shifting the weight thereon or by varying thetension of thesprings thereof, to reduce the differentialgof pressure ascontrolled thereby.

or lesser extent, or by shifting the weight or the springs which loadthe pressure reducing valve associated therewith, the differences inpressure thus set up between the inlet and outlet sides of the systembeing utilized to control the operation Unless such differential ofpressure is adjusted some/material disadvantages 'resultjunless thesystem and particularly the r'adiatoriand drip traps thereof are [inIsubstantially perfect condition.` In other words, by maintaining aconstant differential between the inlet'and outlet sides ofthe systemwhen such differential is not required tocause a proper'flow'of steamthrough the systems under low absolute pressure conditions,'thedifferential of pressure on-the opposite side of the thermostatic trapson the radiators comes excessive and cause these traps to close moretightly to 'maintain this excess difference f 'in pressure. Naturally,thse traps'located closs est to the source of heat supply, where thefriction travelling through the pipes-is very little, will have tomaintain a greater ydifferkrressure than those located 'at the far endof th short circuiting from the steam supply to the vacuum pump, causesa waste of steam through this by-passing, and this/steam in turn tendstol lessen or destroy the vacuum carried inthe system. The circulationto the furtherest radiators then becomes sluggish or ceases entirely anduneven and wasteful heating results. In addition, all of the traps inthe system must remain closed'v during the greatest part of the time `orthis excess Y and on the opposite sides of the driptrapsbescribed anadditional pressure operated subject to a substantially xed pressure,and which differential could not be`- maintained, and this makesitdimcult for the condensation, air and non-condensable gases to beeliminatedy from the radiators, aggravatingthe unsatisfactory conditionstill more. Accordingly, it will be appreciated that unless the pressuredifferential existing between the inlet and outlet sides of the systemis reduced as the vabsolute pressure in the system is reduced,conditions arise kwhich prohibit the most advantageous operation of thesystem to 'be realized.

'Thedesirability of providing a vacuum heating of the vacuum pump toproduce a corresponding,

greater or lesser Vdegree of vacuum at .the outlet vend of the system.

The results sought to be attained by the Jenning'spatent can, by thepractices of the present invention, be obtained in a simpler, quickerand more economical v.manner modification in the construction of thefixed differential system first described and by ing variations in theabsolute pressure of the system at the discharge end thereoftc controlthe admittance of steam to the system, rather than by varying theadmittance of steam to the system to control the degree of vacuum in thesystem as in Jennings.l Additionally, it is to be noted that' a systemconstructed in accordance .with the present invention has an inherentadvantage over'the Jennings system in that in the' system of the presentinvention each time a cycle Jennings system an accelerated flow fofsteam results under the same conditions with all of the attendantdisadvantages. Briefly, this is accomplished by adding to a pressurereducing lvalve of the'xed differential type previously deelement `may,therefore, be atmosphericpressure, on .one

side. and to the pressure at the outlet end of the system on its otherside, and utilizing the movement of or effective force on such pressureoperated element to vary the effects of the main diaphragm on thepressure reducing valve. In other words, this second mentioned pressureoperated element connected to the outlet end of the system on one sideand to the atm'osere on the other side-will produce a force varying inproportion to the variations in pressure at the out- -letend ofthesystem,

and if this force is added tothe force set up on the corresponding sideof the diaphragm of the conventional fixed differential pressurereducing valve. as by being directly connected to such diaphragm or tothe stem of'the valve, or by varying the tension of the spring or weightwhich loads the valve, then the pressure reducing v alve instead of'maintaining a constant differential of pressures between the inlet andoutlet sides of the system will maintain a pressure differential whichwill decrease as the absolutev pressure at the outlet side of the systemhaving means for automatically reducing system decreases.

Thus in accordance with the present invention itis possible by simplycontrolling the vacuum' pump to degree of v vacuum at the outlet end ofthe sysmeans of accomplishing the No. 1,851,434, issued March 29, 1932to I. C. Jenby a relativelysimple employproduce a desired system. v Y

tem, to control the amount o'risteamfnowing fth'rough the system,as-wellla's theeilective head and particularly to Fig. 1which'fillustrates a typical system embodying the present invention,'the numeral rI8 indicates' generally a suitable steam boiler of anyapproved type which discharges steam therefrom-into a steam main I2.

- or diierential of pressure on-v such steam `which Jcauses the ilowthereof through the system. .Referring now to the accompanying drawingsVcomxnerciai type thermostats located so that they would be' affected-byoutside temperatures, could -each be connected to a suitable vacuumoperated regulator for-the motor'84, and each thermostat adjusted sothat its corresponding regulator would make lcontact at a diilerenttemperature than the rest, and the corresponding regulator serve to.eifect operation, of the motor 84 to maintain a degree of vacuum in thesystem lcommensurate provided "with .additional branchesA 2'8 to each ofwhich one or more heat diiusing media', which may be oi.' any suitableor conventional type, but

for the purpose of simplicity in description and.

drawing are here shown as radiatorsl 22, are connected by means ot pipes24. The term radi- 'atorwhen used in the claims is to be interpreted tomean any suitable or conventional heat diilusing media.. 'Ihe outletsides of the radiators 22 are connected by pipes 28 to a vacuum returnline 28, a thermostatic trap 88 being provided in each of the pipes 28at the outlet side of each radiator in accordance with conventionalpractice. The lower ends of the branches 28, which extend below thecorresponding radiators 22, as -well as other low 4points in the system,

' are also connected to the vacuum return line 28 by means oi' pipes 82in which some suitable type of 'sealing means are preferably located.Buch sealing means may. take any usualor desirable 'form such as a waterleg, orince, trap or the like but-for the purpose of illustration areshown as traps 84.

The vacuum return line 28 discharges into a receiver 48 in which thecondensed steam is sep- 'arated from the non-condensable gases andvapors, suchcondensed'steam being'drawn out of Y the receiverandreturned to the boiler by means r of a pump 42 and pipe line 44, thepump 42 be- -lng driven by a motor `48 o! a iloat controlled typeconventionally employed in the art for this purpose. The receiver 48 isconnected by a pipe line 38 with a vacuum pump 82 which discharges intoa separator 88. The pump 82 maybe driven in any suitable manner as, torinstance, by a steam or other engine, steam turbine, Aelectric motor orthe like, an electric motor 84 being shown by way oi' illustration.

Operation of the motor 84 eectsfoperation of the vacuum pump 82 which inturn places the interior of the receiver 48 -and consequently the vacuumreturn line 28 under a partial vacuum, the condensed steamflowing intothe receiver trom the-vacuum return line 28 being separated out in thereceiver and returned tothe `boiler in accordance with conventionalpractice.'4 The vacuum pump 82 may be controlled in any suitable wa'y,that is, by-operating the'motor 84 continuously or intermittently, andwherev continuously it may, i! desired', be accomplished by suitablyvarying the speed of the motor or other prime mover 84 and consequentlythe pump '82 to obtain the desired degree of vacuum in the The motor 84,and consequently the pump 82, may be automatically controlled inaccordance with the demands on the system as based Aon out- :idetemperatures. For. instance, a'plnrality of lcap 82 carryinga which isilxed a two-part housing 88 centrally di.'

pump 82. 1 In order to variably control the iiow of steam into the mainI2 from the boiler I8 a pressure re able or conventional manner with theheating requirements based on the then However, a simpier method,although not automatic, is'shown existing outside temperature.

in the drawings by way of illustration and com- 'fprises a' controlpanel 88 having three control buttons 88, 88 and 82, respectively,thereon. 'I'he control Ibuttons 88 and 82 are each associated maticallycause operation of the motor 54 to maintain a substantially lconstantand respective- -ly-predetermined suction pressure inthe vacuum returnline 28. As a matter of illustration it may .be assumed that when thebutton 88 is operated the motor 84 will be controlled to maintain thevacuum return line 28 under a suction pressure oi.' twenty inches ofmercury and when the but- `ton 82 is operated to control the motor 84the vacuum return line 28 will be maintained under a suction pressure ofni'teen inches of mercury.`

The button 88 may be assumed to operate to control continuous operationof the motor 84 and ducing valveindicated generally at 10 is interposedin the main I2 adjacent the valve I4 but on the down-streamside-thereof. While any suitable type of pressure reducing valve may be.employed for this purpose, one conventional -type of valve is shown indetail in Fig. 2 by way vof illustration and referring to such figure itwill -be noted that it comprises a casing or housing having an inlet 12and an outlet 14, together with a pair of ports 18 connecting the inletand outlet. 'I'he ports .18 are each formed to provide a valve seat attheir upper edges with each of which 'a valve 18 isarranged incooperating relationship.l The valves 18 are rigidly connected togetherby means of a post 88, the construction thus providing a balanced valve-of a conventional .type familiar to those skilled in the ar l Thelowerface of thevalve 10 is `closed Vby a post 84 to the lower end ofvided Iby a ilexible 'diaphragm 88 sealedA at its margins thereto andforming cham-bers 88 and 82 interiorly oi' the casing 88. A stem 84fixed at one end to the valve assembly, includingthe valves 18 and post88, concentrically therewith extends downwardly through ythe post 8| andinto the casing 88 where it is fixed to the center 'oi' the diaphragm88,- a suitable packing indicated generally at 88 serving to seal thestem 84 in its passage through the post 84. This assembly may be loadedtowards open valve position in any suitas, for instance, by

springs, weights, or the like. vWeights are shown .by way ofillustration and arranged ina conventional manner. To' accomplish thisthe lower face oi the casing 88 is provided witha.boss-88 there-258123159l g y onfinxwhich ,the stem '88 is also;suitellbly-vsealedand-theboss-is providedgwlth an offset arm` the link |02 ispivotally -to which one end of connected. The opposite endof the link|02 is pivotally-:connected to a bar |04 to which the lower endof thestemv'84-is also pivotally connected as at |08. Onthe oppositeside ofthe pivot |08 thewboss198is provided with a rigid Toovercome thesediiliculties the operator should adiustthe weight |2 onthe rod |04, orsuch other means as isemployed to load the reducing valve, to reduce thediierential at 'whichthe f valve operates. In other words, whenever achange in the heating-requirements of the sysbifurcated 'armv |08 withinwhich the bar |04 is guided for vertical movement. The bar |04 has a5plurality of weights adjustably mounted thereon.

longitudinally thereof, the fweights ||0 ordinarily remaining xedoncethe -system is adjusted and chamber -80 above the diaphragm 8 8 isconnected by .a pipeline v-| |6 tothe main |2'at a point relatively'close to the valve 10.and'the chamber 82 below. thediaphragmf88isfconnected by a pipe linef`|-|8with the vacuum return lineV28. A tank rims preferabiyinterpcsed in .both lines' Ils and |18; endthese tanks become filled with condensed steam providing a constant headof water on the opposite sides of the diaphragm 88so as to elimiferringnow to Fig. l'it willbe' noted that the'.

nate Vpossible variations in the control due to l variations intheamountspf condensedl steam which might otherwise act -on the oppositesides of the diaphragm.

The .construction thus far jdesc-rated is the con-f vfii'tinal fixeddifferential type of system previously discussed, the construction andarrangement of'the` valve 10 and the control therefor serving,tomaintain a, constant ldiierential of;l

pressure between main` I2 on the outlet side or th' valve 10 andthe'va'cuum return line 28, the amount ofsteam passingthrough the systemand consequently the heating effect of the system varying inversely withthe degree of vacuum in the 'return line 28. For instance, if it isascertained 'that the maximum pressure drop through thesystem to themost remote radiator in subzero. weather is','as a matter ofillustration, three pounds or slx'inches of mercury, and, if steam ata'tem'perat'ure. corresponding toone pound E aug'epressure is requiredto heat the building, under'the'se conditions, then with one poundg'aug'e steam pressure vand the differential valve properly 'adjustedthe vacuu'n in the return line tem is necessary, two-adjustments must bemade b y the operator if proper operating conditions are to result.Thefirst oi these changes is a change in -the degree ofvacuum in thereturn line 2 8 as controlled by the vacuum pump 52, and the second is achange in the differential required to actuate the valve I0 ascontrolledby the position of the weights on the rod |04. A As a matterof fact, however, most operators fail or neglect to adjust thedifferential of the reducing valve and for that reason such systemsoperate at maximum eiliciency only during coldest weather.

The diiiiculties inconnection with the heating system described abovemay be avoided by modifying the control for the pressure reducing valveso that the pressure diierential maintained between the opposite ends ofthe system thereby will vary-in accordance with the variations oi.'absolute pressure at the discharge end of the system.

This, of course, may be accomplished by providing a pressure responsive`element responsive to vvariations in pressure, at the outlet end of thesystem and employing such elements to modify the action of the valve ascontrolled by the diaphragm 88. It may be accomplished by connecting thepressure responsive element to the movable element of the valve, orbyemploying it to change the load on the valve the same as would'beaccomplished by shifting the'weights associated therewith whereweights are used to prevload the valve, or by varying the tension of thespring where springs are employed to preload the valve. Such pressureresponsive element, in 'order to be eective for the purpose described,

must, of course,` exert a force proportional to be subjected to suchpressure variations on one side and to a substantially ilxedpressure' onthe would be four inches of Imercury or thirteen pounds absolute. If, inmoderate weather, the vacum'at'the pump was inches of mercury'orsevenand one-half pounds absolute, then steamvwould'circulate if introducedinto. the system'under a vacuum of nine increased to fifteen 'siredresults. This is the construction illustrated incliesof mercury orapproximately ten and onenalipounds absolute. If, in real .mild weather,al"'acu11m of twenty inches of mercury orfive peunds' absolute wascarried in'the return line', their the Asteam `would circulate'atavacuum equal toffourteenY inches of mercury or appro'ximatelyeightpounds absolute. `I'Iowevelf'. due to the less quentitlinesl ofsteamlreduired by' systemunderl the'latter two condition's','thepressureldrop, due" tofiictio in the systexlfb'e'comes less andjexcess fdifferential ,lens1 1"e"s This canonl'ybe caused by thel radiator anddrip traps" closing during the majorltylof the time to maintain thisexcess differential andjvhlqh they will notdo-.if in worn condition.Under these conditions, causes 'short circuitingof y l 0 tiabsilhiherretu'rn temperature, loss o! 'vacfliltr circeletee. and www 01.Steria 'exceesdifferentialthestean'rthrol'lgh the f otherv side. 'While.such 'ilxed pressure may Abe obtained from any suitablesource,atmospheric pressure will be the simplest and most economical to employas will be readilyappreciated.

A diaphragm such as the diaphragm, 88 andan associated casing is perhapsthe simplest form of pressure responsive element for eiecting this pur..poseand maybe. directly connected to the movable element of the valveto`l accomplish the dein Figs. 1 and 2 and referringparticularly to Fig.2 isl accomplished as follows. A diaphragm casing indicated generally at|'is mounted below the casing 88 in downwardlyspaced relationwithrevspect thereto by means of legs |82.` 'I'he' casing |80 is of the samelgeneral, construction as the' casing 88 and is lnteriorlyprovided witha diaphragm |84l which divides the interior thereof Linto a. lowerchamber |38 and anfupper chamber |88. A stem |40seeure'd to thediaphragm |84 extends upWa-rdlythrou'gh the casing |80 and at.

its upper end is 'suitably' connected to the'- stem '04 by the samepivot pin |08 which connects .thestem 04--to'the rod |04.Consequentlyfthe diaphragms 88 and |84 are connected together' for equalmovement. YThe upper halfof the cain g |38 is provided with an openingv|42 therein connecting consequently will exert a torce on the stem Mand consequently on'the valveassembly ll-80 which at all times isproportional to the pressure in the outlet end of the system. This forceis in addi- `tion to the equivalent i'orce which will be exerted on thelower face of the diaphragm 8l but which in the case of the diaphragm I8is oiset by the varying pressure in the chamber 8l and which pressureacts onits upper face. The' result is that as the pressure in the outletend of the system decreases the relative diierences in pressures act-`ing on the opposite i'aces of the dlaphragms Il and |31 tending to movethe valve 'iii towards closed position increases and as the pressures inthe outlet end of the system increase .the relative difference inpressures acting on the diaphragms 88 and III tending to-close the valvedecrease, thus providing for a greater 'diii'erential between the inletand the outlet end of the system. Obviously by varying the enectivediameter oi' the diaphragm i the force eirerted through the diaphragm|34 tendingato change the diiierential ascontrolled by the diaphragm 8imay be varied so that the actual differential of pressures acting'through the diaphragms to control the valve at various pressures in theoutlet end ci the system may be varied as desired to meet any conditionen' countered in service. Atthe same time, adjust- A ment of the weightsvIll and H2 on the rod I permits a desired ditl'erential between theinlet and outlet ends oi the system to be provided for g atany-particular operating pressure o! the system.

l It will be appreciated from the above description that in a steamheating system constructed in accordance with the present invention theamount of steamri'iowing through a system may be controlled by simplyvarying vthe operation ci the vacuum pump l2 to produce any desireddegree of vacuum in the return line or the'system,- and that anyvariation in the vacuum in the return line will automatically operate toestablish a correspondingly desired diiiferential o! pressure betweenthe inlet and outlet ends of the system and that such diiierential ofpressure will increase with the increase in absolute pressure in thereturn line and will decrease with decrease in absolute pressure in thereturn line. It will also be appreciated that where the control valve isproperly constructed and adjusted it will automatically operate toestablish that differential of pressure between the outlet and inletends of the system most favorable for optimum operating conditionsforany normal operating pressure that is selected for the outlet end ot thesystem either by the operator or by automatic devices. It will also beappreciated that the added expense required to obtain this advantageouscondition oi' operationy is substantially negligible.l

One extremely benencial eiiect of the above described construction is asfollows. With an ordinary pressure reducing valve in a system of thetype described, the moment operation of the vacuum pump is initiated,the differential begween the outlet and the inlet is increased with thet that excess amounts of steam are admitted to the system. The admissionoi this additional steam to the'syatem makes it more diiiicult for thevacuum pump to remove the air. non-condensabie with the pipe line illand consequently to thel gases and condensed water fromthe-system andrequires a much longer operation of the vacuum pump to reduce the vacuumto the desired deree.

With the valve construction employed in con-v junction with the presentinvention each time a cycle of operation of the vacuum pump l! isinitiated the reduced vacuum is iirst apparent in the outlet side of thesystem and is immediately lmade apparent on theunderside of thediaphragms, thus tending to close the pressure reducing valve andreducing the amount of steam that is admitted to the system. It will beappreciated, of course, that the corresponding reduction of pressure inthe outlet end of the system will shortly be apparent at the inlet'endof the system but, because of the addition of the lower diaphragm i, aproportionally greater pull will be exerted on the diapIuagm-tending toclose the valve than would be the case with a conventional type ofcontrol. The result of this construction The above described advantageis not` only important from the standpoint ofmore quickly purging thesystem of air, non-condensable gases and condensed water with consequentshortening oi the operating period of the pump and its operating motorbut it also is eiiective in reducing the peak load of steam used by thesystem. In this connection those skilled in the art lwill understandthat where steam is purchased from a cen. trai heating company on ademand basis, the custemer. in addition to a fiat rate for all steamconsumed during the year, is also charged an extra demand rate. Thisdemand rate is determined ordinarily by the averaging of the severallargest hourly rates of steam consumption during certain periods of theheating season. It these maximum hourly peaks can be reduced, veryconsiderable savings are eii'ected. By reducing the quantity of steamadmitted tothe system each time operation of the vacuum pump isinitiated, the high rate of steam iiow inherent in the usual types ofpressure reduction valves under such of the system nor aliecting theben'eiicial resulte labove described, is that it admirably lends itselfto the provision ot a safety means for the system. In the use ofconventional pressure reducing valves employing a diaphragm or o ersimilar pressure responsive element. shoul the Adiaphragml becomeruptured, as is notvluncommon.`

pressures onopposite sides of the diaphragm or other pressure responsiveelment are equalixed and the valve consequently moves to open positionshowing the full pressure ai. the steam supply -main orv other source otsteam to be applied directly tothe entire heating system. This does noparticular harm where the supply of steam is under relatively lowpressure except to increase .the temperature oi the heated space to anexec sive extent, vbut where the supply of steam is unof which issubjected to the pressure at the inletv der a relatively high pressure,for instance 100 g the larger of which` is pounds per square inch orgreater, dangerous conditions arise, for instance, because of the hightemperatures to which the various parts of the heating system may bebroughtA to and possible rupture of weakened portions of the same. Suchpossibilities may be automatically avoided by a simple expedient intheuse of the valve above described in connection with the presentinvention. This isaccomplished by providing a pipe line such as betweenthe steam main |2, on the downstream side of and preferably adjacent thevalve'10 and the interior of the casing |80 above the diaphragm |84, andproviding a pressure responsive valve indicated generally at |12 in thepipe line |10 so constructed and arranged that it will open to vpermitthe passage of steam through it only upon the presence of a predeter`mined pressure of steam in the supply line |20.. f

While any suitable type of pressure responsive valve may be employed forthis purpose, that shown in Figs. 1 and 2,'and in detail in the latterview,.by way lof illustration consists of a casing |14 having an inletat one end andan outlet at the other end with a valve seat |18interposed therebetween. A valve |18 is arranged in cooperatingrelationship with respectto the seat |18 and is constantly urged towardsseated position by means of a coil spring |80. The force of the spring|80 determines the pressure at which the valve |18 leaves the seat |18to permit the flow of steam through the pipe line |10 tothe casing |80.For instance, where the maximum pressure to open at a gauge pressure offifteen pounds per square inch. The capacity ofthe pipeline 10 is l madegreater than the capacity of the vent opening |42 so that should theupper diaphragm 88 become ruptured and permit the pressure reducingvalve to admit excessivequantities of steam to the heating systemmaterially above the intended maximum pressure, as soon `as steam in themain I2 -on the discharge side of the valve 10 reaches the maximum forcethe valve |1213 designed to operate, in the example assumed fifteenpounds, the valve |18 will open and permit steam under this highpressure to flow into the upperpart of the casing |80. Because the ventopening- |42 is of less capacity than the pipe line |10, under suchconditions a positive pressure willbe built up in the casing |80 abovethe diaphragm |84 and will act to' move the pressure reducing valve 10to closed position thereby to prevent further admission of steam to thesystem and preventing any condition from arising which would permitdangerous pressures to become apparent in the system. o-Where suchsaietydevice is employed it is preferable to connect the vent open-A ing|42 to some suitable pointof discharge as,

' for instance, the outside of the building, by means ofa pipe such as|82. l

' It-will be appreciated from the foregoing that the addition of thediaphragm |84 to the conve'n-y tional nxed diierential type of reducingvalve in a steam heating system. has the effect of increas ing the areaof the lowerface ofthe diaphragm 88 in the conventionalconstructionwithout in'4 creasing the area of the upper` face thereof, so

that differences inv. pressure at the outlet end oi!` the system willvhave a greater effect on the con trol of. the valve than the samedifferences in pressure on the upper` face loi' the diaphragm. Thissuggests the possibility ofemploying al construction embodyin'stwodiaphragms the smallertl end of the system and subjected to the pressureat the outlet end of the system to obtain the same result. Sucha'construction is illustrated in Fig. 3 wherein parts equivalent to theparts illustrated in Fig. 2 are indicated by the same numerals exceptthat such numeral bears a prime mark. y

Referring to Fig.' 3 it will be` noted that. the diaphragm casing 86',similar to the diaphragm casing 88 previously described, is made in twoparts but in this case the lower half of the casing is of greaterdiameter than the upper half. The two halves of the casing in this caseare spaced from each other by means of a spacer having a stepped lowerface. A diaphragm |82 is clamped and sealed between the spacer |80 andthe upper half of the casing 88' and another diaphragm |84 is clampedand sealed betwe'n the lower face of' the spacerA |80 and the lower halfa materially larger eiective area than the' diaphragm |82, for instanceltwice `as great. The stepped lower face of the spacer |80 permits thediaphragm |84 to be effective beyond the effecof the casing 88 isconnected to the steam main |2 in the same manner as the chamber 90previously described; and the chamber 92', corresponding to the chamber92 previously described, is connected to the vacuum return line 28 ofthe system. The two diaphragms are rigidly connected together at theircenters through the stem 94' of the valve so that' they are constrainedto equal movement. As will be real-ized, with this constructionl theeffective area of the diaphragm subject to the pressure at the outletend of the system is greater than the effective area of the diaphragmsubject to the pressure atlthe inlet'.

end of the system and consequently variations in pressure at the outletend of the system will have a greater eiect'on controlling the positionof the valve 18-80 than the, pressures at the inlet end of -the system,and as the degree of' -vacuum inthe chamber 92' increases, its relativeeffect on overcoming thev load of the weight ||2 will increase ascompared to the relative increase of the partial vacuum in the chambertending to add its eiiect to the load |2 and, consequently, thedifferential of pressuresas controlled by the valve 10 will be reduced;In other words. the same ultimate result is obtained by the constructionshown in Fig. 3 as is obtained by the construction illustrated in Fig.2.

'. As previously mentioned, the desired result may also be obtained byemploying a pressure responsive element subject to the pressures at theoutlet end of the system for varying the load proemployed for loadingthe valve. In Fig. 4 a. con- Istruction is illustrated in which thislatter eiect is obtained. Referring to Fig. 4 it will be noted that theconstruction is identical .to that illustrated in Fig. 2 with theexception that the lower diaphragmlcasing |80 and its diaphragm iselimimounted on the rod |04 although the righthand weight H has beeneliminated primarily for the purpose oi! clarincation. The weight il!has been replaced by a weight uz' of slightly different construction andreadily slidable along the rod |04. In this case a metal bellows |00 hasone end thereof rigidly secured' to a bracket |62 ilxed to therod |05 onthe righthand side of the link 02 and the bellows extends in parallelrelation to the rod |04. The opposite end of the bellows |80 isconnected by a short rod |84 with the weight H2'. A coil spring |60within the bellows |80 constantly urges the movable end of the bellows|00 to the right or outwardly of the rod |04 to thus position the weightH2 in a position to exert a maximum load on the valve 'll-80. Theinterior of the bellows |00 is confnected-by afiexible tube |68 with thechamber thus decreasing the effect or the weight uz' in loading thevalve I0-480 and thus reduce the diilerential of pressures between theinlet and outlet ends of the system as controlled by the valve. As thepressure in the outlet end of the Vsystem increases, the pressure on theinterior o! the bellows |00 will decrease thereby permitting the spring|60 to move the weight H2' outwardly away from its Iulcrum and increasethe load on the valve so as to adjust it to maintain.

a greater diilerential .of pressures between the inlet and outlet endsoi the systems. 'Ihe ultimate eiect obtained is, o! course, equivalentto that obtained in the constructions illustrated in Figs. 2 and 3, theonly difference being that the eiIectis obtained by a diiTerent means.

Formal changes may be made in the specifi-c embodiment of the inventiondescribed without departing from the spirit or substance of the broadinvention, the scope of which is commensurate with the appended claims.

What is claimed is:

1. In a steam heating system ofthe class including a steammain, a returnline, a plurality of radiators connected between said main and saidline-pumping means connected with the return line for removing air,non-condensable gases and water of condensation therefrom and a reducingvalve for controlling the admission ot steam to the main, thecombination with said reducing valve of loading means constantly urgingsaid valve toward openv position, and

means for varying the effect of said loading means comprising a nrstchambermeanssubject to the pressure existing in said steam main andhaving a movable wall means so connected tosaid loading means as tooppose the effect oi' said loading means on said valve. and a secondchamber means having movable wall means subject to the pressure existingin said return line and so connected to said loading means as to opposethe eiiect oi' the first mentioned movable wall on said loading means,the area oi the last mentionedI l l wail means exceeding the area of thetiret men- 7s' nated. The lefthand weight ||0 is shown tioned wall meanswhereby variations in pressureI in said return line have a greateriniluence in varying the eflect of said loading means on said valve thanidentical changes in pressure in said steam main.

l2. In a steam heating systemv of the class including a steam main, areturn line, a plurality of radiators connected between said main and 1said line, pumping means connected with the return line for removingnon-condensable gases therefrom and a reducing valve for controlling theadmission of steam to the main, the combination with said reducing valveof pressure responsive meansoperatively connected thereto,

said pressure responsive means including chamber means having movableywall means subject to the pressure existing in the inlet end of the saidsystem and tending to move said valve in one Y direction and chambermeans having movable wall means subject to the pressure existing aty theoutlet end of said system and tending to move said valve in the oppositedirection, said movable wall means being so connected to said valve thatthe force resulting from the difference in pres- -sures acting on saidmovable wall means tends to close said valve. the area oi the lastmentioned movable wall means beingin excess of the area oi' the ilrstmentioned wall means whereby the force exerted byngtheiast mentionedwall means tending to 4move ythe valve in one direction increases at aproportionally greater rate than thel force exerted by the firstmentioned wall means opposing the force of the'second mentioned wallmeans as the absolute pressure in the outlet end -and pressure actuatedmeans for moving saidl valve against the force of the last mentioned,means said pressure actuated means includingmovable wall meansconnected to said valve and subjected to the pressure of said system insaid Vmain tending to urge said valve in one direction and subject tothe pressure existing in saidl re-v turn line tending to urge said valvein the opposite direction, the last mentioned means being so constructedand arranged as to ypresent a -greater area to the eilects of thepressure in said return line than to the eilects of the pressure in saidsteam main whereby to exert,a force on said valve varying with the-variations o! pressure in said system to aj greater degree than theforce vexerted on said valve through variationsloi pressure in saidsteam main.

4. In a steam heating system of the' class including a steam main. areturn line,- a plurality o! radiators connected between said main andsaid line. pumping means connected with the' return line for removingnon-condensable gases therefrom and a reducing valve for controlling theadmission ci' steam to the main, the combination with said reducingvalve oi' loading means constantly urging said valve towards openposition. a` diaphragm connected to said valve and' subject tolvariation; in pressure in said steam main on one tace thereof andsubject to `vitrintions in pressure in said return line on the oppo-l`site fece rfsticreoi, the connection between said l valve of'meansconnected thereto for controlling the operation thereof valve anddiaphragm being such that the difference in pressure on opposite sidesof said diaphragm opposes the eiects of ,said loading means and anadditional diaphragm connected to said valve subject to variations inVpressure in said return line onone face thereof and subject to asubstantially constant pressure on the opposite face thereof forsupplementing the eiects of the first mentioned diaphragm on saidloading means. y

5.-In a steam heating system of the class including a steam main, areturn line, a plurality of radiators connected between said main andsaid line, pumping means connected with the return line for removingnon-condensable gases therefrom and a reducing valve. for controllingface thereof and acting in opposition to said rst diaphragm, thediierence in' forces acting'on said diaphragms opposing` the eiTect ofsaid loading meansfon said valve, the effective area of said seconddiaphragm exceed-ing the effective area of said first diaphragm wherebythe force exerted by said second diaphragm on said valve varies to agreater extent than the force exerted by said rst diaphragm on saidvalve upon equal lchanges in pressure at Opposite ends of said system. y

6. In a steam heating system of the class in-v cluding a steam main, areturn line, a plurality of 'radiators connected between said main andsaid line, pumping means connected with the return line for removingnon-condensable gases therefrom and a reducing valve for controlling theadmission of steam to the main, the combination with said reducing valveof loading means constantly urging said valve towards open position, adiaphragm operatively connected to said valve and subject to thepressures existing in the steam main on oneface thereof and to thepressures existing in saidreturn line on the opposite face thereof, theconnection between said valve and diaphragm being such thatA thedifference in pressures acting on said diaphragm opposes the eiect ofsaid. loading means on said valve, and an additional pressure responsivemeans subject to the pressure existing in said return line on one facethereof and to a substantially constant pressure on the opposite facethereof operatively connected to said loading means for varying theloading eiects thereof during variations of pressure in said return linewhereby to feed greater Y the admission of steam to the mairnthe combi-`comprising movable wall means different areas of which are subject tothe pressure in said main and return line, respectively, said movablewali means having a greater area thereof subjectedto the pressureof saidreturn line than to the pressure of said steam main and being soconstructed and arrangedwith respect to said reducing valve as to tendto close said valve upon increase in pressurein said steam main anddiminution of line, whereby upon initiation operation of said pumpingmeans said movable wall means tendsto close saidvalve.

8. In a steam heating system of the class including a steam main, a`return line, a plurality of-'radiators connected between said main andsaid line, pumping means connected with said return line for removingair and non-condensable y gases therefrom,

means for eilecting cyclic operation of said pumping means, 'and areducing valve for controlling the admission of steam to the main, thecombination with said reducing valve of means connected thereto forcontrolling the operation thereof comprising pressure responsive movablewall means subject to the pressure in said main and return line,respectively,

a greater area of said pressure responsive4 movable wall means beingsubjected to the pressure .of said return line than to the pressure ofsaid steam main and that area of -said pressure responsive movable wallmeans subject to the pressure in said return line in excess of the areathereof subject to the pressure in said main being at least partiallyopposed by a substantially constant pressure, whereby a reduction inpressure in said system is accompanied by a greater force tending tomove said valve towards closed position than the corresponding increasein force tending to move said valve towards open position 9. In a steamheating system of the class including a steam main, a return line, aplurality of radiators connected between said main and said line, apressure reducing valve for controlling the admission of steam to themain, and a pressure responsive element subject to the pressurediierences between said steam main and said return line for controllingsaid Valve, the combination with said valve of means for closing thesame upon the occurrence of conditions equalizing the pressures onopposite sides of said pressure responsive element comprising a secondpressure responsive element connected to said valve, means connectingsaid steam main to one amounts of steam to .said system upon increase inabsolute pressure in said system'and feed lesser amounts of -steam tosaid system with dccrease in absolute pressure in said system.'

7. In a steam heating system of the class inface of said second pressureresponsive element, means for discharging steam from said secondpressure responsive element at a lesser rate than that at which it maybe delivered thereto from said steam main, and pressure responsive meansnormally closing communication through said connecting means operable topermit the flow of steam therethrough upon the presence of an abnormalpositive pressure in said steam main.

10. In a steam heating system of the class including a steam main, areturn line, a plurality of radiators connected between said main andsaid' line, a pressure reducing valve for controiling the admission ofsteam to the main. and a.

pressure responsive element subject to the pressure differences betweensaid steam main and *said return line for controlling said valve, the

combination with said valve of means for closing the same upon theoccurrence of conditions equalizing the pressures on opposite sides ofsaid pressure responsive elementV comprising a. casing,

pressure in said returnv of each cyclev of f valve, said casing having avent therein on one side of said diaphragm, means providing a passagewaybetween said steam main and the vented side of said casing of greatercapacity than said vent, and means associated with said passagenormally'blocking the flow of steam therethrough but operable upon thepresence of an abnormal pressure in said steam main to admit a ow ofsteam from said steam main to said second pressure responsive elementwhereby to eil'ect a closing movement of said valve.

11. `In a steam control valve comprising a casing forming a steampassage and a valve movably mounted therein for controlling the flow ofsteam therethrough, means for controlling the position of said valvecomprising, in combination, a housing xed with respect to said casing, adiaphragm dividing said housing into a pair of chambers,

means sealing said chambers from the atmosphere and said chambers beingrespectivelyv formed for connection to the steam side and the returnside of a. steam heating System, a second housing i'lxed With respect t0said iirst housing, a diaphragm dividing said second housing into a pairof chambers, means connecting said diaphragms ior equal movement, saidsecond hous ing being formed to connect one of said chambers l 2,312,191a diaphragm in said casing connected to said with the return side ofsaid steam heating system, means for connecting the other of saidchambers of said second housing with the steam side of said steamheating system, a valve in said connection operable to admit steam tosaid last mentioned chamber only upon the presence of a predeterminedmaximum pressure in said connection, and means having a lesser flowcapacity than said connection venting said last mentioned chamber to theatmosphere.

12. In a steam control valve comprising acas- 'ing forming a steampassage and a valve movably mounted therein for controlling the flow ofsteam therethrough, means for controlling the position of said valvecomprising, in combination, a housing i'lxed with respect to saidcasing, a pair of diaphragms dividing said housing into three chambers,one of said diaphragrns being of greater diameter than the otherthereof,means for venting the chamber formed between said diaphragmswith the atmosphere, means for connecting the remaining chambers to thesteam` side and the return side, respectively, of a steam heatingsystem, means connecting said diaphragms for equal movement, and meanscon-V necting said diaphragms with said valve.

JOSEPH T. READER.

